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Dynamique spatialement et temporellement hétérogène dans la relaxation lente de la matière molle vitreuse

Abstract : We have investigated dynamical heterogeneities in the slow relaxation of soft glassy systems, using some novel multispeckle light scattering techniques. The first technique, called “Time Resolved Correlation” (TRC), allows one to characterize temporally heterogeneous dynamics. We have optimized TRC working on a model system, a foam. We have proposed several methods to correct from the statistical objects characterising the fluctuations of the dynamics (variance, probability density function, and autocorrelation) the noise contribution due to the finite number of pixel of the CCD camera. The second technique, called “Space and Time Resolved Correlation” (STRC), allows one to characterize spatially heterogeneous dynamics. Thanks to STRC, we have shown that the dynamics of a concentrated lamellar vesicle gel and that of strongly attractive colloidal gel is correlated over surprisingly long distances. Additional measurements on the colloidal gel, performed in a wide range of scattering vectors, have highlighted the dependence of the average dynamics and of its temporally fluctuations with the probed length scale. We proposed a simple model, based on a serie of rearrangements events correlated spatially and random in time, that accounts for the observed behavior.
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https://tel.archives-ouvertes.fr/tel-00154037
Contributor : Agnès Duri <>
Submitted on : Tuesday, June 12, 2007 - 3:36:07 PM
Last modification on : Tuesday, September 15, 2020 - 10:50:21 AM
Long-term archiving on: : Friday, September 21, 2012 - 4:25:56 PM

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  • HAL Id : tel-00154037, version 1

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Agnès Duri. Dynamique spatialement et temporellement hétérogène dans la relaxation lente de la matière molle vitreuse. Analyse de données, Statistiques et Probabilités [physics.data-an]. Université Montpellier II - Sciences et Techniques du Languedoc, 2006. Français. ⟨tel-00154037⟩

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